1. Field of the Invention
The present invention relates to a method and an apparatus for cutting a nonmetallic substrate, and more particularly to a method and an apparatus for cutting a nonmetallic substrate using a laser beam.
2. Description of the Related Art
Semiconductor devices having a high integration and a high effectiveness have been developed as a technology of a semiconductor thin film process has been improved. The semiconductor thin film process has affected a development of an LCD (Liquid Crystal Display) that displays an image using a liquid crystal. The semiconductor devices and LCDs are disposed on a nonmetallic substrate, for example, a silicon substrate or a glass substrate.
Semiconductor devices are manufactured by forming semiconductor chips on a silicon substrate, separating the semiconductor chips from each other, and packaging the semiconductor chips. LCDs are manufactured by forming two or more cells on a glass substrate (referred to as a xe2x80x9cmother boardxe2x80x9d), separating the cells from each other, and assembling the LCD.
The mother board is brittle in comparison with the silicon substrate because the mother board does not have a crystalline structure such as that of the silicon substrate. Hence, the mother board may be easily fractured by a minute crack that occurs at an edge portion of the glass substrate during the separating process.
FIGS. 1A to 1E are schematic views showing a conventional method for cutting a glass substrate.
Referring to FIGS. 1A to 1E, a diamond cutter 10 includes a rotating disc 1 having a diamond 1a disposed at an end portion of a circle shape thereof, a rotating part 2 connected to a central portion of the rotating disc 1 to rotate the rotating disc 1, and a transferring part 3 for transferring the rotating disc 1 and rotating part 2.
The diamond cutter 10 forms a scribe groove 7a around a target region xe2x80x9cLxe2x80x9d on a surface of a glass substrate 7. The target region xe2x80x9cLxe2x80x9d is separated from the glass substrate 7. For instance, when the target region xe2x80x9cLxe2x80x9d has a rectangular shape, the diamond cutter 10 forms the scribe groove 7a at boundaries of the target region xe2x80x9cLxe2x80x9d by moving along lines {circle around (1)}-{circle around (2)}, {circle around (3)}-{circle around (4)}, {circle around (5)}-{circle around (6)}, and {circle around (7)}-{circle around (8)}. By applying a predetermined impact to the portions (xe2x80x9cXxe2x80x9d) around the target region xe2x80x9cLxe2x80x9d, the crack is developed along lines {circle around (1)}-{circle around (2)}, {circle around (3)}-{circle around (4)}, {circle around (5)}-{circle around (6)} and {circle around (7)}-{circle around (8)}. Thus, the target region xe2x80x9cLxe2x80x9d is separated from the glass substrate 7 to form a separated substrate 8.
FIG. 1D shows an enlarged structure of an edge (A) of the separated substrate 8. The separated substrate 8 has a crack 8b disposed at a separated surface 8a. The crack 8b may be randomly developed to any place of the separated substrate 8 due to the impact applied to the portion (X), so that the separated substrate 8 may be cut in an undesired form. Also, the conventional cutting method of the glass substrate 8 causes a lot of glass fragments 7b, so that the glass substrate 7 has to be cleaned through a separated process. Further, the glass fragments 7b causes a contamination of peripheral equipments.
The present invention provides a simplified method of cutting a nonmetallic substrate capable of reducing steps and time for cutting a nonmetallic substrate and reducing contaminants of the substrate.
The present invention also provides an apparatus for cutting a nonmetallic substrate capable of reducing steps and time for cutting a nonmetallic substrate and contaminants of the substrate.
In one embodiment of the invention, a method of cutting a nonmetallic substrate comprises applying a laser beam to first cutting lines of a plurality of cells arranged in a matrix configuration on a nonmetallic substrate to separate the cells from the nonmetallic substrate, wherein each of the cells comprises first, second, third, and fourth edge portions, and wherein each of the first cutting lines is formed along the opposite first and second edge portions; and applying the laser beam to second cutting lines of the cells to separate the cells from each other, wherein each of the second cutting lines is formed along the opposite third and fourth edge portions.
In another embodiment of the present invention, a method of cutting a nonmetallic substrate comprises applying a first laser beam to a first cutting line of a cell disposed on a nonmetallic substrate to form a first crack, wherein the cell comprises first, second, third, and fourth edge portions, the first cutting line is formed along the opposite first and second edge portions, and the first crack is formed on the first and second edge portions; applying a second laser beam along a second cutting line by a predetermined distance from a crossing point to form a crossing crack, wherein the second cutting line intersects the first crack and is in contact with the first crack at the crossing point; applying a third laser beam having energy less than energy of the second laser beam on the second cutting line; cooling the second cutting line using a coolant to form a first scribe crack on a portion of the second cutting line; applying the third laser beam on the crossing crack; and cooling the second cutting line using the coolant to form a second scribe crack on a remained portion of the second cutting line.
In a further embodiment, an apparatus for cutting a nonmetallic substrate comprises a first laser supplying part for applying a first laser beam along a cutting line of a nonmetallic substrate by a predetermined distance from a cutting starting point to form an initial crack, wherein edge portions of the nonmetallic substrate are in contact with the cutting line at the cutting starting point; and a scribe crack forming part for applying a second laser beam having energy less than energy of the first laser beam from the initial crack to an end portion of the cutting line, and for cooling the cutting line using a coolant to form a scribe crack on the cutting line.
According to the method and apparatus of the present invention, an initial crack is previously formed on a nonmetallic substrate by cutting the nonmetallic substrate using laser beams and coolant, and a scribe line is formed on the nonmetallic substrate by applying the laser beam to the initial crack. The nonmetallic substrate is cut along the scribe line by rapidly heating and cooling the portion of the scribe line using the laser beam and coolant. Thus, the method may reduce the steps and time for cutting a nonmetallic substrate and contaminants of the nonmetallic substrate.